/*
 * Copyright 2019 WeBank
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.webank.wedatasphere.linkis.cs.optimize.dfs;

public class MinCostBinaryTree implements BinaryTree{

    Node rootNode;
    BinaryTree left;
    BinaryTree right;
    Double cost;

    public MinCostBinaryTree(Node rootNode) {
        this.rootNode = rootNode;
        if(this.rootNode.visited()){
            return;
        }
        if(rootNode.getLeft() == null){
            this.cost = rootNode.getCost();
            return;
        }
        if(rootNode.getRight() == null){
            this.left = new MinCostBinaryTree(rootNode.getLeft());
            this.cost = this.left.getCost();
            return;
        }

        BinaryTree firstLeft = new MinCostBinaryTree(rootNode.getLeft());
        BinaryTree firstRight = new MinCostBinaryTree(rootNode.getRight());
        Double firstCost = firstLeft.getCost() * rootNode.getLeft().getPriority() + firstRight.getCost()*rootNode.getRight().getPriority();

        rootNode.shift();

        BinaryTree secondLeft = new MinCostBinaryTree(rootNode.getLeft());
        BinaryTree secondRight = new MinCostBinaryTree(rootNode.getRight());
        Double secondCost = secondLeft.getCost() * rootNode.getLeft().getPriority() + secondRight.getCost()*rootNode.getRight().getPriority();

        if(firstCost > secondCost){
            this.left = secondLeft;
            this.right = secondRight;
            this.cost = secondCost;
        } else {
            rootNode.shift();
            this.left = firstLeft;
            this.right = secondRight;
            this.cost = firstCost;
        }
        this.rootNode.visit();
    }

    @Override
    public BinaryTree getLeft() {
        return this.left;
    }

    @Override
    public BinaryTree getRight() {
        return this.right;
    }

    @Override
    public Node getRootNode() {
        return this.rootNode;
    }

    @Override
    public Double getCost() {
        return this.cost;
    }
}
